Hydrogen manufacture

ABSTRACT

A PROCESS FOR PRODUCING HYDROGEN FROM AN EXCESS REFINERY STREAM OR MIXTURE OF REFINERY STREAMS BY HYDROCRACKING, STEAM REFORMING A VAPOROUS FRACTION FROM THE HYDROCRACKING STEP, CONTACTING THE EFFLUENT FROM THE REFORMING STEP ADMIXED WITH ADDITIONAL STEAM WITH A WATER GAS SHIFT CATALYST, RECYCLING A PORTION OF THE HYDROGEN SEPARATED FROM THE SHIFT REACTION TO THE HYDROCRACKING STEP, AND RECOVERING THE REMAINDER OF THE HYDROGEN AS PRODUCT.

Jam 971 H. J. HEPP 3,552,924

HYDROGEN MANUFACTURE Filed Aug. 15, 1966 Nouvavdas im- WATER GAS SHIFTSTEAM REFORMING HEAVY AROMATIC OILp NOliVHVdHS HYDRORACKING A 7'TOR/VEYS United States Patent O 3,552,924 HYDROGEN MANUFACTURE Harold J.Hepp, Bartlesville, kla., assignor to Phillips Petroleum Company, acorporation of Delaware Filed Aug. 15, 1966, Ser. No. 572,316 Int. Cl.'C01b N18 US. Cl. 23-212 8 Claims ABSTRACT OF THE DISCLOSURE A processfor producing hydrogen from an excess refinery stream or mixture ofrefinery streams by hydrocracking, steam reforming a vaporous fractionfrom the hydrocracking step, contacting the effluent from the reformingstep admixed with additional steam with a water gas shift catalyst,recycling a portion of the hydrogen separated from the shift reaction tothe hydrocracking step, and recovering the remainder of the hydrogen asproduct.

This invention relates to a process for producing hydrogen from excessrefinery streams ranging from C to heavy oils.

In most petroleum refineries a complete balance of operations is rarelyachieved. Usually, there is an excess of materials such as naphtha,distillates, gas oils, residual oils, and the like, and there is almostalways a deficiency of hydrogen for use in hydrotreating, hydrogenation,hydrocracking, and similar operations.

This invention is concerned with a process for converting excess liquidpetroleum streams to hydrogen.

Accordingly, it is an object of the invention to provide a process forconverting liquid hydrocarbons to hydrogen. Another object is to providea simple and eflicient process for converting liquid hydrocarbons into Hand CO with recovery of heavy aromatic oils from the process. Otherobjects of the invention will become apparent to one skilled in the artupon consideration of the accompanying disclosure.

In accordance with the invention, a liquid hydrocarbon feed comprisingan excess refinery stream or a mixture of refinery streams ranging fromC to heavy oils is hydrocracked in admixing with hydrogen under severehydrocracking conditions; the hydrocracking efiluent is cooled so as tocondense C and heavier hydrocarbons therein with separate recovery ofthe vaporous fraction and the liquid fraction; the vaporous fraction isadmixed with steam and passed to a steam reforming step in contact witha reforming catalyst to produce principally H CO, and CO the efiiuentfrom the steam reforming step in admixed with additional steam asrequired for reaction and/or cooling, and passed to a Water gas shiftstep for conversion of the CO to CO in contact with a shift reactioncatalyst to produce additional H and the gaseous efiiuent from the shiftreaction is separated into an H stream and a C0 stream, a portion of theH being recycled to the hydrocracking step and the remaining portionbeing recovered as product H The effluent from the hydrocracking step ispartially condensed in indirect heat exchange with water to convert thewater to steam, which is then passed to the steam reforming step and tothe water gas shift reaction. The C and heavier hydrocarbons comprisingthe condensate from the cooling step is passed to a separation zone forrecovery of a heavy aromatic oil as a product of the process and alighter fraction which is recycled to the hydrocracking step. Whencatalytic hydrocracking is used, essentially no heavy aromatic oil ismade, and the total liquid product is recycled to the hydrocrackingzone.

The liquid oil feed is hydrocracked under severe cracking conditions,either pyrolytically or catalytically, such that only about 5 to 12percent of the feedstock is yielded as heavy aromatic hydrocarbons.Operating conditions in the hydrocracking zone or step include a ratioof hydrogen to feedstock in the range of 1,000 to 15,000 cu. ft./bbl., apressure in the range of 250-1000 p.s.i.g, a temperature in the range of750-1350 F., and a liquid hourly space velocity in the range of 0.1 to1-0 (catalytic) or a contact time of 0.1 to 10 minutes (pyrolytic). Itis preferred to utilize a catalyst but pyrolytic hydrocracking isfeasible. Any hydrocracking catalysts having both a hydrogenationcomponent and a cracking component may be utilized. Preferred catalystsinclude the metals, oxides and/or sulfides of nickel, moylbdenum,platinum, palladium, ruthenium, tungsten, and/or cobalt deposited onalumina, silica-alumina, silica-zirconia, or silica-magnesia support.

Conditions in the steam reforming zone include a steam to dry gas molratio in the range of 1:1 to 10:1, a pressure in the range of 250-1000p.s.i.g, a temperature in the range of 1250-1600 F., and a dry gashourly space velocity in the range of 500 to 10,000. The preferredcatalyst is nickel on alundum (aluminum oxide) but any of the steamreforming catalysts known to the industry may be utilized.

In the water gas shift reaction, conditions include a steam to dry gasmol ratio in the range of 0.521 to 3:1, a pressure in the range of300-500 p.s.i.g, a temperature in the range of 450-850 F., a dry gashourly space velocity in the range of 500 to 5,000, and, preferably, aniron oxide-chromium oxide catalyst. Other water gas shift reactioncatalysts known to the industry, such as zinccopper chromite, may beutilized.

Separation of H and CO from the efliuent from the water gas shiftreaction is effected, for example, by absorption of the CO inethanolamine in conventional manner. Any manner of effecting thisseparation is within the scope of the invention.

The C and heavier oil fraction downstream of the condensation step iseither separated by fractional distillation or any other conventionalmeans into a heavy aromatic oil and a lighter fraction which is recycledto the hydrocracking step (pyrolytic hydrocracking) or is recycledwithout such a separation step (catalytic hydrocracking). The heavyaromatic oil is a marketable product of the operation, for example, forcarbon black manufacture.

A more complete understanding of the invention may be had by referenceto the accompanying schematic drawing, which is a flow or arrangement ofapparatus suitable for performing the invention.

'Referring to the drawing, a suitable liquid oil feed in line 10 is fedto hydrocracking unit 12 in admixture with hydrogen from line -14 andthe liquid oil fraction from line 16' obtained as hereinafter disclosed.The hydrocracked efiiuent is passed via line 18 thru indirect heatexchanger 20 and cooled therein by heat exchange with water introducedthru line 22 which converts at least the major portion of the water tosteam. The heat exchange in exchanger .20 is controlled so as tocondense the C and heavier hydrocarbons and leave most of the C andlighter hydrocarbons in vapor form. The efiiuent from exchanger 20passes thru line 24 into knock-out drum 26, the liquid oil beingwithdrawn from the bottom of the drum thru line 128 and the overheadvapor being passed thru line 30 to steam reforming zone 32 in admixturewith steam from line 34 which connects with line 22.

The efiiuent from steam reforming zone 32 consisting essentially of HCO, and CO along with steam, is passed via line 36 to water shiftreaction zone 38 in admixture with added steam 'from line 40. The watershift reaction converts CO to CO with the formation of additionalhydrogen, the effluent from this reaction being passed via line 42 toseparation or absorption zone 44 where it is contacted with ethanolaminefrom line 45 The ethanolamine, containing CO is Withdrawn from this zonethru line 46 and passed to CO recovery means (not shown) to conditionthe ethanolamine for reuse in the process. The CO is recovered as aproduct of the process. The hydrogen remaining in vapor form aftercontacting with the ethanolamine is recovered thru line 48, a minorportion being recycled thru line 14 to the hydrocracking operation inzone 12 and the major portion being recovered as hydrogen for use inrefinery processes or for any other suitable use.

The liquid C to heavy aromatic oil fraction recovered from knock-outdrum 26 thru line 28 is passed to separation zone 50 in which the oilstream is fractionated into a heavy aromatic oil fraction and a lighteroil fraction, the former being recovered as a product of the processthru line 52 and the latter being passed thru lines 16 and 10 to thehydrocracking step, or is recycled directly to the hydrocracking stepvia line 51.

The following example is illustrative of the process of the inventionbut is not to be construed as unnecessarily limiting the invention:

EXAMPLE Hydrogen 40 Methane 40 Ethane 17 C 3 These product gases arethen reacted with steam at a mol ratio of steam to dry gas of 2:1 and adry gas hourly space velocity of 1500 over a nickel-alundum catalyst atabout 500 p.s.i.g. and 1500 F. to convert the hydrocarbons to hydrogenand the oxides of carbon. This mixture is further reacted withadditional steam over an iron oxide-chromium oxide shift catalyst usinga steam to dry gas ratio of 0.6: 1, a pressure of 400 p.s.i.g., atemperature of 800 F., and a dry gas hourly space rate of 1500 toconvert the carbon monoxide to carbon dioxide with formation ofadditional H and the carbon dioxide in the resulting stream is absorbedin ethanolamine. This operation produces 31,000 cubic feet of hydrogenper barrel of kerosene of which 8000 cubic feet are recycled. Thus, thenet hydrogen production is 23,000 cubic feet per barrel of kerosene.

The foregoing example clearly demonstrates the effectiveness of theprocess in producing large amounts of hydrogen per barrel of feed, thenet hydrogen production being 23,000 cu. ft./bbl. of kerosenedistillate. Other excess refinery streams of liquid oils, alone or inadmixture, are amenable to hydrogen production in accordance with theinvention.

Certain modifications of the invention will become apparent to thoseskilled in the art and the illustrative details disclosed are not to beconstrued as imposing unnecessary limitations on the invention.

I claim:

1. A process for producing H from a feed comprising available refineryoils ranging from C to heavy oils, which comprises the steps of:

(a) hydrocracking a stream of said oils in admixture with H under severeconditions to form principally C and lighter hydrocarbons;

(b) cooling the cracked eflluent from step (a) to condence C and heavierhydrocarbons including heavy aromatic oils and leave C and lighterhydrocarbons in vapor form;

(b) into a heavy aromatic oil fraction as a product and (c)catalytically reforming the vapor effluent from step (b) in the presenceof steam to convert same principally to H CO, and CO (d) contacting theeffluent from step (c) in admixture with steam with a Water gas shiftreaction catalyst to increase the production of H (e) selectivelyremoving CO from the eflluent from step (d) thereby leaving the H in thevapor form;

(f) recycling a portion of the H of step (e) to step (g) recovering theremaining portion of H from step (e) as product,

(h) separating the C and heavier fraction of step (b) into a heavyaromatic oil fraction as a product and a lighter fraction, and

(i) recycling the lighter fraction of step (h) to step (a).

2. The process of claim 1 wherein step (a) is effected pyrolytically andonly about 5 to 12 weight percent of the feed is yielded as heavyaromatics.

3. The process of claim 1 wherein step (b) is effected by indirect heatexchange with water to form steam and resulting steam is used as steamin steps (c) and (d).

4. A process for producing hydrogen from a feed comprising essentially akerosene distillate boiling in the range of about 350 to 520 R, whichcomprises the steps of:

(a) hydrocracking said feed in admixture with H under severe conditionsof a ratio of H to feed in the range of 1000 to 15,000 cubic feet perbarrel, a pressure in the range of 250 to 1000 p.s.i.g., a temperaturein the range of 75 to 1350 F., and a contact time in the range of 0.1 to10 minutes in the absence of a catalyst, to form principally C andlighter hydrocarbons;

(b) cooling the cracked eflluent from step (a) to condense C and heavierhydrocarbons including heavy aromatic oils and leave 0;, and lighterhydrocarbons in vapor form; (0) passing the vapor efiiuent from step (b)to a catalytic steam reforming step including a nickelalundum catalyst,a steam to dry gas mol ratio in,

the range of 1:1 to 10:1, a pressure in the range of 250 to 1000p.s.i.g., a temperature in the range of 1250 to 1600 F., and a dry gashourly space velocity in the range of 500 to 10,000, to convert saidvapor efiiuent principally to H C0, and CO (d) passing the efiluent fromstep (c) in admixture with steam to a water gas shift step with a steamto total dry gas mol ratio in the range of 0.5: 1 to 3: 1, a pressure inthe range of 300 to 500 p.s.i.g., a temperature in the range of 450 to850 F., a dry gas hourly space velocity in the range of 500 to 5000, andan iron oxide-chromium oxide catalyst, to increase the production ofhydrogen;

(e) passing the effluent from step (d) to a separation absorption stepwhere it is contacted with ethanolamine to remove CO and to leave H inthe vapor form;

(f) recycling a portion of the H of '(e) to step and (g) recovering aremaining portion of H from step (e) as product.

5. The process of claim 4 wherein step (a). is effected pyrolyticallyand only about 5 to 10 Weight percent of the feed is yielded as heavyaromatics.

6. The process of claim 4 including the step of: (h) recycling thecondensate of step (b) to step (a). 7. The process of claim 4 includingthe steps of: '(h) separating the C and heavier fraction of step alighter fraction; and (i) recycling the lighter fraction of step (h) tostep (a). 8. A process for producing H from a feed comprising availablerefinery oils ranging from C to heavy oils, which comprises the stepsof:

(a) hydrocracking a stream of said oils in admixture with H under severeconditions to form principally C and lighter hydrocarbons, said severeconditions including a ratio of H to feed in the range of 1000 to 15,000cu. ft./bbl., a pressure in the range of 250 to 1,000 p.s.i.g., atemperature in the range of 750 to 1350 F., and a contact time in therange of 0.1 to min. in the absence of a catalyst;

(b) cooling the cracked efi'luent from step (a) to condensed C andheavier hydrocarbons including heavy aromatic oils and leave C andlighter hydrocarbons in vapor form;

(0) catalytically reforming the vapor efiluent from step (b) to convertsarne principally to H CO, and CO using a nickel-alundum catalyst, asteam to dry gas mol ratio in the range of 1:1 to 10:1, a pressure inthe range of 250 to 1000 p.s.i.g., a temperature in the range of 1250 to1600 F., and a dry gas hourly space velocity in the range of 500 to10,000;

(d) contacting the efiluent from step (c) in admixture with steam in asteam to total dry gas mol ratio in the range of 0.521 to 3:1, at apressure in the range of 300 to 500 p.s.i.g., a temperature in the rangeof 450 to 850 F., a dry gas hourly space velocity in the range of 500 to5000, with a water gas shift reaction catalyst comprising an ironoxide-chromium oxide catalyst, to increase the production of H (e)selectively removing CO from the efiluent from step ((1) thereby leavingthe H in the vapor form;

(f) recycling a portion of the H of step (e) to step (a); and

(g) recovering the remaining portion of H from step (e) as product.

References Cited UNITED STATES PATENTS 6/ 1961 DuBois Eastman et al.

208-107 8/1965 Brooks et a1 260290 12/ 1966 Carson 260672 1/ 1968 DuBoisEastman et al.

208143 7/ 1956 Kaulakis 23212X 4/1962 Tucker 23212X 9/1964 Jahnig 23-2l24/ 1966 Ramella 23212 8/1966 Pfcfferle 23-212X 1/1967 Marshall, Jr23-212 5/ 1967 Paterson 23212-X 1/ 1968 Johnson et al. 23-212X 5/1968Cromeans 23--212 6/1968 Habermehl et al. 23-212X FOREIGN PATENTS 1/ 1961Great Britain 260672 EDWARD STERN, Primary Examiner US. Cl. X.R.

